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Comparison of methods for the determination of Tesla turbine performance

100%

Rusin K. , Wróblewski W. , Strozik M.

Journal of Theoretical and Applied Mechanics

2019

tom Vol. 57 nr 3

563--575

A numerical and experimental investigation of the Tesla turbine is presented in the paper. The experiment is conducted for various inlet pressure and load. The roughness of the rotor disc is determined as it is a key factor to obtain high turbine efficiency and power. The numerical investigations are performed for the same conditions as in the experiment. The computational results are compared with the analytical model. Comparison of performance characteristics show a relatively good agreement between the experiment and CFD. The analytical model overestimates distributions of pressure and circumferential velocities, although the predicted power is on the similar level as in the experiment and CFD.

Experimental analysis on unsteady characteristics of sheet/cloud cavitating Venturi flow under the effect of dissolved air

88%

Malekshah E. H. , Wróblewski W. , Bochon K. , Majkut M. , Rusin K.

Archives of Thermodynamics

2022

tom Vol. 43, no 3

63--84

The highly dynamic and unsteady characteristics of the cavitating flow cause many negative effects such as erosion, noise and vibration. Also, in the real application, it is inevitable to neglect the dissolved air in the water, although it is usually neglected in the previous works to reduce the complexity. The novelty of the present work is analysing the impact of dissolved air on the average/unsteady characteristics of Venturi flow by conducting sets of experimental tests. For this purpose, two different amounts of dissolved air at five pressure levels (i.e. five different sets of cavitation numbers) were considered in the study of cavitating flow inside a Venturi nozzle. The fast Fourier transform analysis of pressure fluctuations proved that the shedding frequency reduces almost by 50% to 66%, depending on the case, with adding the amount of dissolved air. However, the reduction of 14% to 25% is achieved by the vibration transducers. On the other hand, the cavity enlarges as well as bubbly flow is observed in the test chamber at a higher level of dissolved air. Furthermore, it is observed that the re-entrant jet, as the main reason for the cavity detachment, is more effective for the detachment process in cases with a lower level of dissolved air, where the re-entrant jet front penetrates more toward the leading edge.

Experimental studies of packed-bed Thermal Energy Storage system performance

75%

Ochmann J. , Bartela Ł. , Rusin K. , Jurczyk M. , Stanek B. , Rulik S. , Waniczek S.

Journal of Power Technologies

2022

tom Vol. 102, nr 1

37--44

This paper contains an experimental analysis of a heat storage tank's heat loss and exergy efficiency using a basalt porous bed as a storage material. The basic parameters of the laboratory bench with measuring equipment are presented and the experimental procedure is discussed. The methodology for evaluating the energy potential of the heat storage process for large-scale energy storage systems is described. The main novelty of the presented system is the application of the slenderness of the heat accumulator, which corresponds to the development of the system in a post-mining shaft. Based on the analysis of the experiment, the exergy cycle efficiency of the heat storage unit was determined to equal 52.3%, and the energy efficiency equal to 96.6%.